Ceiling-embedded air conditioner

ABSTRACT

A ceiling-embedded air conditioner includes, a casing, a motor including an output shaft protruding downward, the output shaft being driven to rotate about an axis, a main plate fixed to the output shaft and extending radially outward, a turbofan including an impeller, a heat exchanger passed through by air that is sent from the turbofan. And the main plate includes, a tapered portion, a recess formed to be recessed radially inward from the tapered portion, the recess being defined by a cylindrical plate portion extending along the axis, and a disk plate portion extending radially outward from the upper end of the cylindrical plate portion. And an opening is formed in the cylindrical plate portion, the opening penetrates the cylindrical plate portion in the radial direction, and configured such that a circulation flow that exits from the impeller and flows around above the main plate passes through the opening.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of priority to Japanese PatentApplication Number 2020-015374 filed on Jan. 31, 2020. The entirecontents of the above-identified application are hereby incorporated byreference.

TECHNICAL FIELD

The disclosure relates to a ceiling-embedded air conditioner.

RELATED ART

As an example of an air conditioner, a ceiling-embedded air conditioneris widely used. The ceiling-embedded air conditioner mainly includes acasing embedded in an indoor ceiling, a motor including an output shaftthat rotates about an axis extending in a vertical direction, aturbofan, a main plate that fixes the turbofan to the output shaft, anda heat exchanger that surrounds the turbofan. By the rotation of theturbofan, indoor air is taken in from the central portion of the casing,and is supplied indoors as cold air or warm air by passing through theheat exchanger.

As a specific example of such a ceiling-embedded air conditioner, theone described in Japanese Patent Application Laid-Open No. 2000-227231is known. In this apparatus, the main plate has a conical shape whosediameter increases radially outward as advancing from the lower side tothe upper side. Most of the air taken into the casing flows upward alongthe outer surface of the main plate and is then sent to the radiallyouter heat exchanger by the turbofan. On the other hand, a part of theair taken into the casing forms a circulation flow that goes around theturbofan from above and flows into the upper side of the main plate. Inthe apparatus described in Japanese Patent Application Laid-Open No.2000-227231, this circulation flow is used as air for cooling the motor.The air that has cooled the motor joins the main flow (i.e., the flowalong the outer surface of the main plate) again through the openingformed in the main plate.

Here, in the case where the angle at which the main flow and thecirculation flow is close to a right angle, a mixing loss occurs betweenthe main flow and the circulation flow. As a result, the performance ofthe air conditioner may be affected. Therefore, in the apparatusaccording to Japanese Patent Application Laid-Open No. 2000-227231, abulging portion for guiding the flow direction of the circulation flowis additionally provided as a new component in the opening of the mainplate.

SUMMARY

However, the attachment of the separate component to the main plate asdescribed above leads to a complicated configuration and an increase inthe number of components and the number of manufacturing steps. As aresult, the manufacturing cost may increase.

The present disclosure has been made to solve the above problems, and anobject of the present disclosure is to provide a ceiling-embedded airconditioner having a simpler configuration and further improvedperformance.

In order to solve the problems described above, there is provided aceiling-embedded air conditioner including, a casing including a suctionport formed in the center of a lower portion of the casing and an outletport formed around the suction port, a motor provided in the casing andincluding an output shaft protruding downward, the output shaft beingdriven to rotate about an axis extending in a vertical direction, a mainplate fixed to the output shaft in the casing and extending radiallyoutward of the axis; a turbofan including an impeller attached to alower surface of the main plate in the casing at intervals in acircumferential direction, the impeller being configured to send airintroduced from the suction port radially outward, a heat exchangerprovided to surround the turbofan in the casing and passed through byair that is sent from the turbofan and flows toward the outlet port. Andthe main plate includes, a tapered portion extending to increase indiameter radially outward as advancing upward, a recess formed to berecessed radially inward from the tapered portion over thecircumferential direction, the recess being defined by a cylindricalplate portion extending along the axis, and a disk plate portionextending radially outward from the upper end of the cylindrical plateportion. And an opening is formed in the cylindrical plate portion, theopening penetrating the cylindrical plate portion, and configured suchthat a circulation flow that exits from the impeller and flows aroundabove the main plate passes through the opening.

According to the present disclosure, it is possible to provide aceiling-embedded air conditioner having a simpler configuration andfurther improved performance.

BRIEF DESCRIPTION OF DRAWINGS

The disclosure will be described with reference to the accompanyingdrawings, wherein like numbers reference like elements.

FIG. 1 is a cross-sectional view illustrating a configuration of aceiling-embedded air conditioner according to an embodiment of thepresent disclosure.

FIG. 2 is a cross-sectional view illustrating a configuration of a mainplate according to an embodiment of the present disclosure.

FIG. 3 is a side view illustrating a configuration of an openingaccording to an embodiment of the present disclosure.

FIG. 4 is a side view illustrating a modified example of an openingaccording to an embodiment of the present disclosure.

FIG. 5 is a side view illustrating another modified example of anopening according to an embodiment of the present disclosure.

FIG. 6 is a side view illustrating a further modified example of anopening according to an embodiment of the present disclosure.

DESCRIPTION OF EMBODIMENTS First Embodiment Configuration ofCeiling-embedded Air Conditioner

Hereinafter, a ceiling-embedded air conditioner 100 according to a firstembodiment of the present disclosure will be described with reference toFIGS. 1 to 3. As illustrated in FIG. 1, the ceiling-embedded airconditioner 100 includes a casing 1, a motor 2, a main plate 3, aturbofan 4, a heat exchanger 5, and a bell mouth 6.

The casing 1 is embedded in a ceiling wall C of a building. The casing 1has a rectangular shape when viewed from below, and is recessed upwardto form a space therein. To be specific, the casing 1 includes a panel1A exposed to the ceiling surface Ca and a box-shaped cabinet 1Bprovided above the panel 1A. The panel 1A includes a panel body 11,which is a rectangular frame body, and a grill 12, which is a suctionport 11A provided at the center of the lower portion. The panel body 11forms an outlet port 11B around the suction port 11A.

The motor 2 is provided at a central portion of a bottom surface 1Sfacing downward inside the cabinet 1B. The motor 2 includes a motor body21 that accommodates a coil, a magnet, or the like, and an output shaft22 that protrudes vertically downward from the motor body 21. The outputshaft 22 is rotationally driven about an axis Ac extending in thevertical direction.

A main plate 3 extending radially outward from the output shaft 22 isfixed to the output shaft 22. The configuration of the main plate 3 willbe described later. A turbofan 4 is attached to a lower surface of themain plate 3. The turbofan 4 includes an impeller 41 including aplurality of blades arranged at intervals in a circumferentialdirection, and a disk-shaped shroud 42 covering the impeller 41 frombelow. The main plate 3 and the turbofan 4 rotate with the rotation ofthe output shaft 22, and the air sucked from the suction port 11A issent outward radially.

An annular heat exchanger 5 surrounding the turbofan 4 is providedradially outside the turbofan 4. The heat exchanger 5 is a part of arefrigerant circuit having a refrigeration cycle. The air (main flow Fm)sent to the heat exchanger 5 by the turbofan 4 exchanges heat with therefrigerant when passing through the heat exchanger 5. Thus, the airflowing out to the outer circumferential side of the heat exchanger 5becomes cold air or warm air. The air flows downward along the sidesurface of the cabinet 1B and is supplied into the room from the outletport 11B.

A bell mouth 6 fixed to an upper portion of the panel body 11 isdisposed below the turbofan 4. The bell mouth 6 is provided to guide theair introduced from the suction port 11A and send the air to theturbofan 4. The bell mouth 6 has a conical shape in which the diametergradually decreases from the lower side toward the upper side.

Configuration of Main Plate

Next, the configuration of the main plate 3 will be described in detailwith reference to FIGS. 2 and 3. As illustrated in FIG. 2, the mainplate 3 includes a bottom plate portion 31, a lower tapered portion 32,a cylindrical plate portion 33, a disk plate portion 34, an uppertapered portion 35, and an upper plate portion 36, which are integrallyconnected in this order from the inside to the outside radially.

The bottom plate portion 31 has a circular shape extending radiallyoutward from the outer circumferential surface of the output shaft 22. Alower tapered portion 32 is connected to an outer circumferential edgeof the bottom plate portion 31. The lower tapered portion 32, from thelower side to the upper side, extends radially from the inner side tothe outer side as advancing from the lower side to the upper side. Thatis, the lower tapered portion 32 has a conical shape whose diametergradually increases as advancing upward. An outer circumferential edgeof the lower tapered portion 32 is located below the motor body 21.

A cylindrical plate portion 33 is connected to an outer circumferentialedge of the lower tapered portion 32. The cylindrical plate portion 33has a cylindrical shape centered on the axis Ac. That is, thecylindrical plate portion 33 extends along the axis Ac in across-sectional view. The cylindrical plate portion 33 is formed with aplurality of openings h penetrating the cylindrical plate portion 33 inthe radial direction. As illustrated in FIG. 3, the plurality ofopenings h are rectangular and are arranged at intervals in thecircumferential direction. As illustrated in FIG. 2, the openings h areeach formed at a position corresponding to the lower end of the motorbody 21 in the vertical direction.

A disk plate portion 34 is connected to an upper end edge of thecylindrical plate portion 33. The disk plate portion 34 extends radiallyoutward from the upper end of the cylindrical plate portion 33. The diskplate portion 34 has an annular shape centered on the axis Ac. Thecylindrical plate portion 33 and the disk plate portion 34 intersect ata right angle in a cross-sectional view including the axis Ac. Here, theterm “right angle” refers to a substantially right angle, and a designtolerance and a manufacturing error are included in the term “rightangle”. That is, it is possible to adopt a configuration in which thecylindrical plate portion 33 and the disk plate portion 34 intersectwith each other at a slight obtuse angle. The recess R is defined by thecylindrical plate portion 33 and the disk plate portion 34.

An upper tapered portion 35 is connected to an outer circumferentialedge of the disk plate portion 34. Similarly to the lower taperedportion 32, the upper tapered portion 35 extends radially from the innerside to the outer side as advancing from the lower side to the upperside That is, the lower tapered portion 32 has a conical shape whosediameter gradually increases as advancing upward. Preferably, the lowertapered portion 32 and the upper tapered portion 35 are on the sameconical surface. An upper plate portion 36 is connected to an outercircumferential edge of the upper tapered portion 35. The upper plateportion 36 has an annular shape extending radially outward from an outercircumferential edge of the upper tapered portion 35. The impeller 41 ofthe turbofan 4 described above is attached to the lower surfaces of theupper plate portion 36 and the upper tapered portion 35. Note that inFIG. 2, an illustration of the impeller 41 is omitted.

Operational Effects

Next, the operation of the ceiling-embedded air conditioner 100 will bedescribed. To operate the ceiling-embedded air conditioner 100, themotor 2 is first driven. By driving the motor 2, the output shaft 22,the main plate 3, and the turbofan 4 rotate about the axis Ac. As theturbofan 4 rotates, indoor air is taken in through the suction port 11A.The air is sent to the turbofan 4 through the bell mouth 6, and then ispressure-fed radially outward to form a main flow Fm (see FIG. 1 or 2).The main flow Fm flows along the lower surface of the main plate 3. Thatis, the main flow Fm flows from the inside to the outside radially asadvancing from the lower side to the upper side. Most of the main flowFm exchanges heat with the refrigerant by passing through the heatexchanger 5, and becomes cold air or warm air to be supplied into theroom from the outlet port 11B.

On the other hand, a part of the main flow Fm does not flow toward theheat exchanger 5, but flows to go around above the main plate 3, therebyforming a circulation flow Fc. The circulation flow Fc flows toward theinner circumferential side along the upper surface of the main plate 3,and then cool s the motor body 21 by being blown to the motor body 21.The circulation flow Fc that has cooled the motor body 21 flowsdownward, and then joins the main flow Fm on the lower surface side ofthe main plate 3 through the openings h formed in the main plate 3.

Here, when the angle at which the main flow Fm and the circulation flowFc join is close to a right angle, a mixing loss occurs between the mainflow Fm and the circulation flow Fc. As a result, the air does not flowsmoothly in the casing 1, which may affect the performance of the airconditioner. Therefore, in the present embodiment, the recess R isformed in the main plate 3, and the openings h are formed in thecylindrical plate portion 33 that defines the recess R.

According to the above configuration, the cylindrical plate portion 33in which the openings h are formed extends along the axis Ac. Thus, thecirculation flow Fc is blown radially outward from the openings h. Here,the main flow Fm flows upward as advancing radially outward. Since thecirculation flow Fc is blown radially outward, the angle at which themain flow Fm and the circulation flow Fc join together can be reduced.As a result, the mixing loss generated between the main flow Fm and thecirculation flow Fc can be reduced. Further, in the above-describedconfiguration, such a reduction in mixing loss can be realized only byforming the recess R in the main plate 3 without increasing the numberof components. This makes it possible to improve the performance of theceiling-embedded air conditioner 100 while suppressing an increase inmanufacturing cost.

Other Embodiments

The embodiments of the present disclosure have been described above.Various changes and modifications can be made to the above configurationwithout departing from the scope of the present disclosure. For example,in the above-described embodiment, an example in which the openings hare rectangular and are arranged at intervals in the circumferentialdirection has been described. However, it is also possible to adopt theconfigurations illustrated in FIGS. 4 to 6.

In the example of FIG. 4, the positions of the openings h2 adjacent toeach other in the axis Ac direction are different. Further, thecircumferential end portions t1 of the openings h2 overlap each other inthe vertical direction.

According to the above configuration, the circulation flow Fc can beguided uniformly over the entire region in the circumferentialdirection. As a result, the pressure loss at the openings h2 can befurther reduced. In addition, the above configuration can make itpossible to suppress a decrease in strength of the main plate due to theformation of the plurality of openings h2. As a result, the durabilityof the ceiling-embedded air conditioner 100 can be further improved.

In the example of FIG. 5, the end edges L1 of the openings h3 in thecircumferential direction extend in a direction inclined with respect tothe axis Ac, and the end edges L1 of the openings h3 adjacent to eachother overlap in the vertical direction. With this configuration, thesame operational effects as those of the example of FIG. 4 can beobtained.

In the example of FIG. 6, a plurality of openings h4 are arranged atintervals in the circumferential direction to form a row, and aplurality of (two) rows R1 and R2 are provided at intervals in thevertical direction. The positions of the openings h4 in thecircumferential direction are different from each other in rows adjacentto each other in the vertical direction. With this configuration aswell, it is possible to obtain the same operational effects as those ofthe examples of FIGS. 4 and 5.

Notes

The ceiling-embedded air conditioner 100 described in each of theembodiments is grasped as follows, for example.

(1) A ceiling-embedded air conditioner 100 according to a first aspectincludes, a casing 1 including a suction port 11A formed in the centerof a lower portion of the casing 1 and an outlet port 11B formed aroundthe suction port 11A, a motor 2 provided in the casing 1 and includingan output shaft 22 protruding downward, the output shaft 22 being drivento rotate about an axis Ac extending in a vertical direction, a mainplate 3 fixed to the output shaft 22 in the casing 1 and extendingradially outward of the axis Ac, a turbofan 4 including an impeller 41attached to a lower surface of the main plate 3 in the casing 1 atintervals in a circumferential direction, the impeller 41 beingconfigured to send air introduced from the suction port 11A radiallyoutward, a heat exchanger 5 provided to surround the turbofan 4 in thecasing 1, and passed through by air that is sent from the turbofan 4 andflows toward the outlet port 11B. And the main plate 3 includes, atapered portion 32 and 35 extending to increase in diameter radiallyoutward as advancing upward, and a recess R formed to be recessedradially inward from the tapered portion 32 and 35 over thecircumferential direction, the recess R being defined by a cylindricalplate portion 33 extending along the axis Ac and a disk plate portion 34extending radially outward from the upper end of the cylindrical plateportion 33. And an opening h is formed in the cylindrical plate portion33, the opening h penetrating the cylindrical plate portion 33 in theradial direction, and configured such that a circulation flow Fc thatexits from the impeller 41 and flows around above the main plate 3passes through the opening.

According to the above configuration, the cylindrical plate portion 33in which the opening h is formed extends along the axis Ac. Thus, thecirculation flow Fc is blown radially outward from the opening h. Here,a main flow Fm flowing upward along the main plate 3 is formed outsidethe main plate 3. More specifically, the main flow Fm flows upward asadvancing radially outward. Since the circulation flow Fc blows outradially outward as described above, the angle at which the main flow Fmand the circulation flow Fc join together can be reduced. As a result,the mixing loss generated between the main flow Fm and the circulationflow Fc can be reduced. Further, in the above-described configuration,such a reduction in mixing loss can be realized only by forming therecess R in the main plate 3 without increasing the number ofcomponents. This makes it possible to improve the performance of theceiling-embedded air conditioner 100 while suppressing an increase inmanufacturing cost.

(2) In the ceiling-embedded air conditioner 100 according to a secondaspect, a plurality of openings h2 are arranged in the circumferentialdirection, and the circumferential end portions t1 of the openings h2adjacent to each other overlap in the vertical direction.

According to the above configuration, the plurality of openings h2 arearranged in the circumferential direction, and the circumferential endportions t1 of the adjacent openings h2 overlap in the verticaldirection. Thus, the circulation flow can be guided uniformly over theentire region in the circumferential direction. As a result, thepressure loss at the openings h2 can be further reduced.

(3) In the ceiling-embedded air conditioner 100 according to the thirdaspect, each of the openings h2 has a rectangular shape, thelongitudinal direction of the rectangular shape is in thecircumferential direction, and the positions of the openings h2 adjacentto each other in the vertical direction are different from each other.

According to the above configuration, each of the openings h2 has arectangular shape, and the positions of the adjacent openings h2 in thevertical direction are different from each other. Accordingly, thecirculation flow Fc can be guided uniformly over the entire region inthe circumferential direction, and a decrease in strength of the mainplate 3 due to the formation of the plurality of openings h2 can besuppressed to be small. As a result, the durability of theceiling-embedded air conditioner 100 can be further improved.

(4) In the ceiling-embedded air conditioner 100 according to a fourthaspect, the end edge L1 in the circumferential direction of each of theopenings h3 extends in a direction inclined with respect to the axis Ac,and the end edges L1 of the openings h3 adjacent to each other overlapin the vertical direction.

According to the above configuration, the end edge L1 of each of theopenings h3 in the circumferential direction is inclined, and theadjacent end edges L1 overlap each other in the vertical direction.Thus, the circulation flow Fc can be uniformly guided over the entireregion in the circumferential direction.

(5) In the ceiling-embedded air conditioner 100 according to a fifthaspect, the plurality of openings h4 are arranged at intervals in thecircumferential direction to form rows R1 and R2, the plurality of rowssuch as R1 and R2 are arranged at intervals in the vertical direction,and the positions of the plurality of openings h4 in the circumferentialdirection are different between the rows R1 and R2 adjacent in thevertical direction.

According to the above configuration, the plurality of openings h4 arearranged in the circumferential direction and the vertical direction,and the positions of the openings h4 in the circumferential directionare different between the rows R1 and R2 adjacent to each other in thevertical direction. Accordingly, the circulation flow Fc can be guidedover the entire region in the circumferential direction uniformly, and adecrease in strength of the main plate 3 due to the formation of theplurality of openings h4 can be suppressed to be small. As a result, thedurability of the ceiling-embedded air conditioner 100 can be furtherimproved.

While preferred embodiments of the invention have been described asabove, it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirits of the invention. The scope of the invention, therefore, isto be determined solely by the following claims.

1. A ceiling-embedded air conditioner, comprising: a casing including asuction port formed in the center of a lower portion of the casing andan outlet port formed around the suction port; a motor provided in thecasing and including an output shaft protruding downward, the outputshaft being driven to rotate about an axis extending in a verticaldirection; a main plate fixed to the output shaft in the casing andextending radially outward of the axis; a turbofan including an impellerattached to a lower surface of the main plate in the casing at intervalsin a circumferential direction, the impeller being configured to sendair introduced from the suction port radially outward; and a heatexchanger provided to surround the turbofan in the casing and passedthrough by air that is sent from the turbofan and flows toward theoutlet port, wherein the main plate includes a tapered portion extendingto increase in diameter radially outward as advancing upward, and arecess formed to be recessed radially inward from the tapered portionover the circumferential direction, the recess being defined by acylindrical plate portion extending along the axis and a disk plateportion extending radially outward from the upper end of the cylindricalplate portion, and an opening is formed in the cylindrical plateportion, the opening penetrating the cylindrical plate portion in theradial direction, and configured such that a circulation flow that exitsfrom the impeller and flows around above the main plate passes throughthe opening.
 2. The ceiling-embedded air conditioner according to claim1, wherein a plurality of the openings are arranged in thecircumferential direction, and the circumferential end portions of theplurality of the openings adjacent to each other overlap in the verticaldirection.
 3. The ceiling-embedded air conditioner according to claim 1,wherein each of the plurality of the openings has a rectangular shape,the longitudinal direction of the rectangular shape is in thecircumferential direction, and the positions of the plurality of theopenings adjacent to each other in the vertical direction are differentfrom each other.
 4. The ceiling-embedded air conditioner according toclaim 2, wherein each of the plurality of the openings has a rectangularshape, the longitudinal direction of the rectangular shape is in thecircumferential direction, and the positions of the plurality of theopenings adjacent to each other in the vertical direction are differentfrom each other.
 5. The ceiling-embedded air conditioner according toclaim 1, wherein end edges of the plurality of the openings in thecircumferential direction extend in a direction inclined with respect tothe axis, and the end edges of the plurality of the openings adjacent toeach other overlap in the vertical direction.
 6. The ceiling-embeddedair conditioner according to claim 2, wherein end edges of the pluralityof the openings in the circumferential direction extend in a directioninclined with respect to the axis, and the end edges of the plurality ofthe openings adjacent to each other overlap in the vertical direction.7. The ceiling-embedded air conditioner according to claim 1, whereinthe plurality of the openings are arranged at intervals in thecircumferential direction to form a row, a plurality of rows arearranged at intervals in the vertical direction, and positions of theplurality of the openings in the circumferential direction are differentbetween the plurality of rows adjacent in the vertical direction.
 8. Theceiling-embedded air conditioner according to claim 2, wherein theplurality of the openings are arranged at intervals in thecircumferential direction to form a row, a plurality of rows arearranged at intervals in the vertical direction, and positions of theplurality of the openings in the circumferential direction are differentbetween the plurality of rows adjacent in the vertical direction.
 9. Theceiling-embedded air conditioner according to claim 3, wherein theplurality of the openings are arranged at intervals in thecircumferential direction to form a row, a plurality of rows arearranged at intervals in the vertical direction, and positions of theplurality of the openings in the circumferential direction are differentbetween the plurality of rows adjacent in the vertical direction. 10.The ceiling-embedded air conditioner according to claim 4, wherein theplurality of the openings are arranged at intervals in thecircumferential direction to form a row, a plurality of rows arearranged at intervals in the vertical direction, and positions of theplurality of the openings in the circumferential direction are differentbetween the plurality of rows adjacent in the vertical direction. 11.The ceiling-embedded air conditioner according to claim 5, wherein theplurality of the openings are arranged at intervals in thecircumferential direction to form a row, a plurality of rows arearranged at intervals in the vertical direction, and positions of theplurality of the openings in the circumferential direction are differentbetween the plurality of rows adjacent in the vertical direction. 12.The ceiling-embedded air conditioner according to claim 6, wherein theplurality of the openings are arranged at intervals in thecircumferential direction to form a row, a plurality of rows arearranged at intervals in the vertical direction, and positions of theplurality of the openings in the circumferential direction are differentbetween the plurality of rows adjacent in the vertical direction.